They come with speeches, placards, power point presentations and drums. Some with body paint and bows and arrows. Others with suits and business plans. Almost all driven by a desire for radical change.

"Come re-invent the world" is the call to the People's summit, which has opened in Rio de Janeiro to counter what many participants see as the malign influence of capitalism at the Rio+20 United Nations sustainable development conference now taking place on the outskirts of the city.

Two hundred civil society groups - including environmentalists, unions, religious groups and indigenous tribes – will take part in the nine-day event, which is expected to climax with a rally of 50,000 people on the 20th June.